Labelling tracks in Timeline causing slowdown

We have a weird issue on one of our Avid media composer 8.7.2, running on Z800 and Mojo DX. We label our tracks on the timeline for obvious reasons but in one of our offline suites if the editor opens a sequence with the tracks labelled the system grinds to a halt, no scrubbing, trimming and even opening a menu takes upwards of 30 seconds.